How many water molecule are involved in light-dependent reactions to produce TWOmolecules of oxygen?A. 2B. 3C. 4D. 5

To determine how many water molecules are involved in the light-dependent reactions to produce two molecules of oxygen, we can analyze the process of photosynthesis, specifically the oxygen-evolving complex.

Breakdown of the Problem

1. In the light-dependent reactions, water molecules are split (photolysis) to generate oxygen and electrons.
2. Each water molecule yields one molecule of oxygen.

Relevant Concepts

• The general equation for the photolysis of water can be represented as: $2 \text{H}_2\text{O} \rightarrow 4 \text{H}^+ + 4 \text{e}^- + \text{O}_2$
• This reaction shows that two water molecules produce one molecule of oxygen.

Analysis and Detail

1. From the photolysis equation, we can see that to produce one molecule of oxygen, two water molecules are required.
2. Since the question asks for the number of molecules of water involved to produce two molecules of oxygen:
   • $2 \text{O}_2$ would require $2 \times 2 = 4 \text{H}_2\text{O}$.

Verify and Summarize

• We confirmed that 2 water molecules produce 1 oxygen molecule.
• Therefore, to produce 2 oxygen molecules, 4 water molecules are indeed needed.

Final Answer

The answer is C. 4.